Well I'm glad you admitted this is your view, but I think it's factually wrong. Logically, I can think of no reason why someone should be credited for things outside of his or her control. I don't think people deserve credit for being tall, having rich parents, or having a better defense behind them, or for getting lucky on balls in play. Pitchers are paid to minimize the success of hitters, not to get lucky. Hitters have fared worse per at-bat against Kershaw, but due to circumstances largely out of his control, opposing players have scored earned runs at a higher rate than against Pelfrey. Ultimately though, your definition of the "better" pitcher to date - which includes luck, fielding, and so on - is meaningless due to all the noise. So when you say not to trade Pelfrey because he's been the Twins best pitcher, you are really saying, don't trade Pelfrey because I value luck over skill.